Samsung 750 User Manual page 116

Ib
Do not disconnect or connect
the
RS-232C coble
while the
Computer or the DLP TV is operating.
It may couse serious
damage
10
the
Computer or
the
DLP TV.
Ib
If
the
PC is not
properly
configured,
the
RS- 232C
connection may not
work properly.
For
further
details,
refer
10
the
Computer s
product
documentation.
fl.
1
lIJl
a
Connect the DLP DTV using the serial port.
Serial Port Settings (Select Standard RS232)
Specification RS-232C
Bit Rate
9600 bps
DetlI
Bita
a bits
Partty None
StoDBIta
1 bit
Flow Control None
Serial Gommunication Protocol
Command Packet
Struc~ure
Response Packet Stru§ture
• A command packet consists of 7 bytes in total.
• The two bytes Ox08 and Ox22 signify that the packet is for serial communication.
• The following 4 bytes represent a
pr~fined
command that
can
be defined by the user.
• The last byte is the checksum which checks the validity of the current packet.
Header [2 Byte): Pre-defined values fixed to oxoa and Ox22.
Cmd1 [1 Byte): The first value of the code defined in the command list (Hexadecimal)
Cmd2 [1 Byte]: The second value of the code defined in the command list (Hexadecimal)
Cmd3 [1 Byte): The third value of the code defined in the command list (Hexadecimal)
Value [1 Byte): Input parameter for the command (Defau~: 0) (Hexadecimal)
CS [1 Byte): Checksum (the 2's complement of the sum of all the values except for the CS value.)
• Success • Fail
I
oxo31 OxOC
I
OxF1
I I
oxo31 OxOC
I
OxFF
I
When the received packet from an external device has a valid value,
a Success packet is sent. Otherwise, a Fail packet is sent.
A Fail packet is sent if:
• The received packet length is not equal to 7 bytes.
• The 2 byte packet header value is not equal to oxoa, 0x22.
• The check sum is incorrect.
Failure detection
by
an external device
An external device classifies the packet as Fail if it does not receive
a Success packet within 100ms.
Communication Sequence
• PC
Creates a command packet and sends it through RS232C.
• DLP DTV
Receives a packet and parses the packet.
Determines whether it is a success or fail, and transmits the Ack packet to the PC.
Controls the DLP DTV with the parsed command.
• PC
Waits for the Ack packet.
Prepares the next command, if a Success packet arrives immediately.